Objective To design an open shape memory alloy artificial vertebral body that can be used to reconstruct the vertebral body in spine diseases, such as thoracic-lumbar spine tumors, burst fracture of the vertebrae, kyphosis and scol iosis, and to evaluate the biomechanical stabil ity of lumbar functional segment unit after insertion with the shape memoryalloy artificial vertebral body. Methods The open shape memory alloy artificial vertebral body with nickel-titanium (NiTi)alloy was made. Eight fresh spine specimens (T14-L5) from normal adult porcine were used to detect the range of motion (ROM) in 4 models and were divided into 4 groups: intact vertebrae served as group A; pedicle screw fixation of T15, L1, L3, and L4 was given in group B; after total resection of L2, it was reconstructed by open shape memory alloy artificial vertebral body combined with pedicle screw fixation of T15, L1, L3, and L4 in group C; and after total resection of L2, it was reconstructed by titanium cage vertebral body combined with pedicle screw fixation of T15, L1, L3, and L4 in group D. The three-dimensional ROM of flexion, extension, left/right lateral bending, and left/right rotation in T15-L1, L1-3, and L3,4 segments were detected in turn by the spinal three-dimensional test machine MTS-858 (load 0-8 N•m). Results Compared with group A, groups B, C, and D had good stabil ity in flexion, extension, left/right lateral bending, and left/right rotation, showing significant differences (P lt; 0.05). There was no significant difference in the degree of each motion between group B and group C (P gt; 0.05). Group C had less degree of motion in T15-L1 and L3,4 segments than group D, showing significant differences (P lt; 0.05), but there was no significant difference in L1-3 segment (P gt; 0.05). Conclusion The open shape memory alloy artificial vertebral body has a reasonable structure and good biomechanical stabil ity, it can be used to stabil ize the spinal segment with pedicle screw fixation.
ObjectiveTo perfect the surgical process that trachea could be reconstructed by nickel-titanium (Ni-Ti) alloy stent wrapped with autologous pericardium, and to evaluate the effectiveness and observe the complications. MethodsIn the experiment, twelve healthy Bama suckling pigs with weight of 18-25 kg were selected. The pericardium was harvested to cover the Ni-Ti alloy stent. The compound artificial trachea was used to reconstruct long-segmental (6 cm) trachea defect. The effectiveness, complications, the properties, and growth rate of the new mucosa of the artificial trachea lumen were observed. ResultsOf 12 pigs, 2 died soon because of hemorrhage and infection, respectively; 7 died at 2-4 months after operation because of hyperplasia at the middle section and blockage of phlegm plug; 3 survived after 42 weeks postoperatively, but accompanied with dyspnea symptom. At 1, 2, 3, 4, and 5 months after operation, the average crawl length of the new trachea mucosa was 1, 3, 5, 7, and 10 mm, respectively; the occurrence rates of anastomotic stenosis were 0 (0/10), 0 (0/9), 0 (0/4), 33.3% (1/3), and 33.3% (1/3) respectively; and the occurrence rates of scar hyperplasia in the middle of lumen were 20% (2/10), 66.7% (6/9), 75.0% (3/4), 66.7% (2/3), and 100% (3/3), respectively. At 7 months postoperatively, the bronchoscopy examination showed that the scar in central part of artificial trachea had the trends of stagnation, softening, and narrowing, and respiratory symptom had the trend of slight ease. Hyperplasia tissue could be found in central part of artificial trachea by autopsy and was verified to be fiber cells and necrotic tissue by pathology examination. ConclusionNi-Ti alloy stent with autologous pericardium can insure that the reconstructed tracheal lumen is unobstructed, and support the trachea epithelium regeneration; the main factors of the death of the experimental animals are the lumen hyperplasia of the artificial trachea and the blockage of the secondary phlegm plug.
ObjectiveTo evaluate the biomechanical effect of a nickel-titanium (Ni-Ti) three-dimensional memory alloy mesh in treating a canine tibial plateau collapse fracture model and to lay a foundation for further experiments in vivo.MethodsSixteen tibial plateau specimens of 8 adult Beagle dogs were harvested. Twelve specimens were taken to prepare canine tibial plateau collapse fracture models (Schatzker type Ⅲ) and randomly divided into groups A, B, and C, with 4 specimens in each group. Four normal tibia specimens were used as blank control group (group D). In groups A and B, the bone defects were repaired with Ni-Ti three-dimensional shape memory alloy mesh combined with autologous bone and simple autologous bone respectively, and fixed with the lateral plate and screw. In group C, the bone defect was directly fixed with the lateral plate and screw. By using a biomechanical tester, a progressive load (0-1 700 N) was loaded vertically above the femoral condyle. The maximum failure load was recorded and the stiffness was calculated according to the load-displacement curve.ResultsThe maximum failure loads in groups A, B, C, and D were (1 624.72±7.02), (1 506.57±3.37), (1 102.00±1.83), and (1 767.64±24.56) N, respectively; and the stiffnesses were (129.72±20.83), (96.54±27.05), (74.96±17.70), and (169.01±35.62) N/mm, respectively. The maximum failure load and stiffness in group A were significantly higher than those in groups B and C, but which were significantly lower than those in group D (P<0.05).ConclusionNi-Ti three-dimensional memory alloy mesh combined with autologous bone can repair the Schatzker type Ⅲ tibial plateau collapse fracture, which has better biomechanical properties than simple autologous bone grafting.
Objective To compare the effectiveness between three-dimensional (3D) printed porous titanium alloy cage (3D Cage) and poly-ether-ether-ketone cage (PEEK Cage) in the posterior lumbar interbody fusion (PLIF). Methods A total of 66 patients who were scheduled to undergo PLIF between January 2018 and June 2019 were selected as the research subjects, and were divided into the trial group (implantation of 3D Cage, n=33) and the control group (implantation of PEEK Cage, n=33) according to the random number table method. Among them, 1 case in the trial group did not complete the follow-up exclusion study, and finally 32 cases in the trial group and 33 cases in the control group were included in the statistical analysis. There was no significant difference in gender, age, etiology, disease duration, surgical segment, and preoperative Japanese Orthopaedic Association (JOA) score between the two groups (P>0.05). The operation time, intraoperative blood loss, complications, JOA score, intervertebral height loss, and interbody fusion were recorded and compared between the two groups. Results The operations of two groups were completed successfully. There was 1 case of dural rupture complicated with cerebrospinal fluid leakage during operation in the trial group, and no complication occurred in the other patients of the two groups. All incisions healed by first intention. There was no significant difference in operation time and intraoperative blood loss between groups (P>0.05). All patients were followed up 12-24 months (mean, 16.7 months). The JOA scores at 1 year after operation in both groups significantly improved when compared with those before operation (P<0.05); there was no significant difference between groups (P>0.05) in the difference between pre- and post-operation and the improvement rate of JOA score at 1 year after operation. X-ray film reexamination showed that there was no screw loosening, screw rod fracture, Cage collapse, or immune rejection in the two groups during follow-up. At 3 months and 1 year after operation, the rate of intervertebral height loss was significantly lower in the trial group than in the control group (P<0.05). At 3 and 6 months after operation, the interbody fusion rating of trial group was significantly better in the trial group than in the control group (P<0.05); and at 1 year after operation, there was no significant difference between groups (P>0.05). ConclusionThere is no significant difference between 3D Cage and PEEK Cage in PLIF, in terms of operation time, intraoperative blood loss, complications, postoperative neurological recovery, and final intervertebral fusion. But the former can effectively reduce vertebral body subsidence and accelerate intervertebral fusion.
ObjectiveTo review the current research and application progress of three-dimentional (3D) printed porous titanium alloy after tumor resection, and provide direction and reference for the follow-up clinical application and basic research of 3D printed porous titanium alloy. MethodsThe related literature on research and application of 3D printed porous titanium alloy after tumor resection in recent years was reviewed from three aspects: performance of simple 3D printed porous titanium alloy, application analysis of simple 3D printed porous titanium alloy after tumor resection, and research progress of anti-tumor 3D printed porous titanium alloy. Results3D printing technology can adjust the pore parameters of porous titanium alloy, so that it has the same biomechanical properties as bone. Appropriate pore parameters are conducive to inducing bone growth, promoting the recovery of skeletal system and related functions, and improving the quality of life of patients after operation. Simple 3D printed porous titanium alloy can more accurately match the bone defect after tumor resection through preoperative personalized design, so that it can closely fit the surgical margin after tumor resection, and improve the accuracy and efficiency of the operation. The early and mid-term follow-up results show that its application reduces the postoperative complications such as implant loosening, subsidence, fracture and so on, and enhances the bone stability. The anti-tumor performance of 3D printed porous titanium alloy mainly includes coating and drug-loading treatment of pure 3D printed porous titanium alloy, and some progress has been made in the basic research stage. ConclusionSimple 3D printed porous titanium alloy is suitable for patients with large and complex bone defects after tumor resection, and the anti-tumor effect of 3D printed porous titanium alloy can be achieved through coating and drug delivery.
Objective To evaluate the effectiveness of using titanium alloy trabecular bone three-dimensional (3D) printed artificial vertebral body in treating cervical ossification of the posterior longitudinal ligament (OPLL). Methods A retrospective analysis was conducted on clinical data from 45 patients with cervical OPLL admitted between September 2019 and August 2021 and meeting the selection criteria. All patients underwent anterior cervical corpectomy and decompression, interbody bone graft fusion, and titanium plate internal fixation. During operation, 21 patients in the study group received titanium alloy trabecular bone 3D printed artificial vertebral bodies, while 24 patients in the control group received titanium cages. There was no significant difference in baseline data such as gender, age, disease duration, affected segments, or preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), vertebral height, and C2-7 Cobb angle (P>0.05). Operation time, intraoperative blood loss, and occurrence of complications were recorded for both groups. Preoperatively and at 3 and 12 months postoperatively, the functionality and symptom relief were assessed using JOA scores, VAS scores, and NDI evaluations. The vertebral height and C2-7 Cobb angle were detected by imaging examinations and the implant subsidence and intervertebral fusion were observed. Results The operation time and incidence of complications were significantly lower in the study group than in the control group (P<0.05), while the difference in intraoperative blood loss between the two groups was not significant (P>0.05). All patients were followed up 12-18 months, with the follow-up time of (14.28±4.34) months in the study group and (15.23±3.54) months in the control group, showing no significant difference (t=0.809, P=0.423). The JOA score, VAS score, and NDI of the two groups improved after operation, and further improved at 12 months compared to 3 months, with significant differences (P<0.05). At each time point, the study group exhibited significantly higher JOA scores and improvement rate compared to the control group (P<0.05); but there was no significantly difference in VAS score and NDI between the two groups (P>0.05). Imaging re-examination showed that the vertebral height and C2-7 Cobb angle of the two groups significantly increased at 3 and 12 months after operation (P<0.05), and there was no significant difference between 3 and 12 months after operation (P>0.05). At each time point, the vertebral height and C2-7 Cobb angle of the study group were significantly higher than those of the control group (P<0.05), and the implant subsidence rate was significantly lower than that of the control group (P<0.05). However, there was no significant difference in intervertebral fusion rate between the two groups (P>0.05). Conclusion Compared to traditional titanium cages, the use of titanium alloy trabecular bone 3D-printed artificial vertebral bodies for treating cervical OPLL results in shorter operative time, fewer postoperative complications, and lower implant subsidence rates, making it superior in vertebral reconstruction.